Assessing Health Consequences of Vitamin D Fortification Utilizing a Societal Experiment Design: Methodological Lessons Learned from the D-Tect Project.

By utilizing historical changes in Danish legislation related to mandatory vitamin D fortification of margarine, which was implemented in the mid 1930s and abruptly abandoned in June 1985, the studies in the D-tect project investigated the effects of vitamin D on health outcomes in individuals, who during gestation were exposed or unexposed to extra vitamin D from fortified margarine. This paper reviews and narratively summarizes the analytic approaches alongside the results of the societal fortification experiment studies from the D-tect project and addresses the challenges in designing societal experiment studies and evaluating their results. The latter are discussed as lessons learned that may be useful for designers of similar studies, expected to be extensively utilized while researching the health consequences of the COVID-19 pandemic by comparing individuals born before and after the epidemic. In the D-tect project, 16 articles based on the societal fortification experiment were published analyzing 10 different outcomes and using different statistical approaches. Lessons learned included the detail of the analysis of the historical information on the exposure, availability and validity of the outcome data, variety of analytical approaches, and specifics concerning vitamin D effect evaluation, such as consideration of the influence of sunshine or season. In conclusion, the D-tect project clearly demonstrated the cost-effectiveness and research potential of natural- or societal-experiment-based studies.

The Role of Vitamin D in the Development of Diabetes Post Gestational Diabetes Mellitus: A Systematic Literature Review.

Women diagnosed with gestational diabetes mellitus (GDM) are more likely to later develop diabetes. Evidence from some previous reviews suggests that low vitamin D status during pregnancy increases the risk of developing GDM, but whether vitamin D during pregnancy also influences the risk of diabetes post GDM is less well studied. Thus, the aim of this systematic literature review was to summarize the current available literature on that topic. This review considered observational studies and randomized controlled trials (RCTs). Five databases were searched. The risk of bias of the included studies was assessed. A total of six studies were included: three observational studies and three RCTs. Findings were inconsistent across the six included studies. However, when considering RCTs only, the findings more strongly suggested that vitamin D supplementation during and after pregnancy did not have an influence on markers of diabetes development or diabetes development post GDM. This systematic review highlights inconsistent findings on the associations between vitamin D supplementation or concentration during and after pregnancy and markers of diabetes development or diabetes development post GDM; and although results from randomized interventional studies more strongly suggested no associations, the conclusion holds a high degree of uncertainty.

Neonatal Vitamin D Status and Risk of Asthma in Childhood: Results from the D-Tect Study.

BACKGROUND: low vitamin D status in pregnancy can influence the offspring's lung function and contribute to childhood asthma development. The objective of this study was to examine the influence of neonatal vitamin D status on the development of asthma among children age 3-9 years in a large population sample. METHOD: in a case-cohort study utilizing a Danish biobank and register data we examined the association between neonatal 25-hydroxyvitamin D3 (25(OH)D3) concentrations and incidence of asthma among children aged 3-9 years. Cases of asthma (n = 911) were randomly selected among all cases of asthma in the Danish National Patient Register from children born between 1992 and 2002. The sub-cohort (n = 1423) was randomly selected among all children born in the same period. We used a weighted Cox proportional hazard model assessing the hazard of first asthma diagnoses by quintiles of 25(OH)D3. RESULTS: the median 25(OH)D3 (interquartile range) for asthma cases was 23 nmol/L (14-35) and the sub-cohort 25 nmol/L (14-40). The hazard ratio for developing asthma between ages 3 and 9 years was lower for children in the fifth quintile of neonatal 25(OH)D3 compared to children in the first quintile, both in the unadjusted (0.61 95% CI: 0.46-0.80) and adjusted (0.55 95% CI: 0.39-0.77) analyses. CONCLUSION: the results from our study suggest that higher neonatal vitamin D concentration may reduce the risk of developing childhood asthma at ages 3-9 years, indicating that neonatal vitamin D status as a proxy of vitamin D status during the prenatal period is important for normal immune- and lung development.

Substitution of sugar-sweetened beverages for other beverages and the risk of developing coronary heart disease: Results from the Harvard Pooling Project of Diet and Coronary Disease.

Sugar-sweetened beverage (SSB) intake is associated with metabolic disorders. The reduction of SSB intake has been promoted to prevent death and disability from chronic diseases. We investigated the association between SSB intake and the risk of coronary events and death, and assessed if substitution of coffee, tea, milk, fruit juice and artificially-sweetened beverages (ASB) for SSBs was associated with a reduced risk of coronary events and death. This was a follow-up study in which data from six studies were pooled and standard observational analyses were performed. Diet intake was assessed at baseline by food-frequency questionnaires. Hazard ratios (HRs) with 95% confidence intervals for the incidence of coronary events and deaths were calculated by Cox proportional hazards regression. The effect of substituting another beverage for SSBs was calculated by taking the difference in the individual effect estimates. During the median 8.2-year follow-up, 4248 coronary events and 1630 coronary deaths were documented among 284,345 individuals. 355 ml daily increase of SSB intake was associated with an increased risk of coronary events (HR: 1.08; 95%CI: 1.02, 1.14) and possibly coronary death (HR: 1.05; 95%CI: 0.96, 1.16). Substitution analyses suggested that replacing SSBs with coffee (HR: 0.93; 95%CI: 0.87, 1.00) or ASB (HR: 0.89; 95%CI: 0.83, 0.97), might be associated with a lower risk of developing coronary events. We found that SSB intake was associated with an increased risk of coronary events and possibly coronary death. Our findings also suggest that replacing SSB's with ASBs or coffee may lower the risk of developing CHD.

Exposure to Vitamin D Fortification Policy in Prenatal Life and the Risk of Childhood Asthma: Results From the D-Tect Study.

Prenatal vitamin D insufficiency may be associated with an increased risk of developing childhood asthma. Results from epidemiological studies are conflicting and limited by short follow-up and small sample sizes. The objective of this study was to examine if children born to women exposed to the margarine fortification policy with a small dose of extra vitamin D during pregnancy had a reduced risk of developing asthma until age 9 years, compared to children born to unexposed women. The termination of a Danish mandatory vitamin D fortification policy constituted the basis for the study design. We compared the risk of inpatient asthma diagnoses in all Danish children born two years before (n = 106,347, exposed) and two years after (n = 115,900, unexposed) the termination of the policy. The children were followed in the register from 0-9 years of age. Data were analyzed using Cox proportional hazards regression. The Hazard Ratio for the first inpatient asthma admission among exposed versus unexposed children was 0.96 (95%CI: 0.90-1.04). When stratifying by sex and age, 0-3 years old boys exposed to vitamin D fortification showed a lower asthma risk compared to unexposed boys (HR 0.78, 95%CI: 0.67-0.92). Prenatal exposure to margarine fortification policy with extra vitamin D did not affect the overall risk of developing asthma among children aged 0-9 years but seemed to reduce the risk among 0-3 years old boys. Taking aside study design limitations, this could be explained by different sensitivity to vitamin D from different sex-related asthma phenotypes in children with early onset, and sex differences in lung development or immune responses.

In utero exposure to extra vitamin D from food fortification and the risk of subsequent development of gestational diabetes: the D-tect study.

BACKGROUND: The primary aim of this study was to assess whether exposure during fetal life to extra vitamin D from food fortification was associated with a reduction in the risk of subsequently developing gestational diabetes mellitus (GDM). Furthermore, we examined whether the effect of the vitamin D from fortification differed by women's season of birth. METHODS: This semi-ecological study is based on the cancellation in 1985 of the mandatory policy to fortify margarine with vitamin D in Denmark, with inclusion of entire national adjacent birth cohorts either exposed or unexposed to extra vitamin D in utero. The identification of GDM cases later in life among both exposure groups was based on the Danish national health registers. Logistic regression analyses generating odds ratios (ORs) and 95% confidence intervals (95% CIs) were performed. RESULTS: Women who were prenatally exposed to the extra vitamin D from fortification tended to have a lower risk of subsequently developing GDM than unexposed women (OR 0.87, 95%CI 0.74,1.02, P = 0.08). When analyses were stratified by women's season of birth, exposed women born in spring had a lower risk of developing GDM compared to unexposed subjects (OR 0.68, 95%CI 0.50,0.94, p = 0.02). CONCLUSION: This study suggests that prenatal exposure to extra vitamin D from mandatory fortification may lower the risk of developing gestational diabetes among spring-born women. TRIAL REGISTRATION: This study is part of the D-tect project, which is registered on clinicaltrials.gov: NCT03330301 .

A retrospective analysis of a societal experiment among the Danish population suggests that exposure to extra doses of vitamin A during fetal development may lower type 2 diabetes mellitus (T2DM) risk later in life.

Vitamin A deficiency has been associated with impaired fetal pancreatic development and increased risk of developing type 2 diabetes mellitus (T2DM). In 1962, mandatory margarine fortification with vitamin A was increased by 25 % in Denmark. We aimed to determine whether offspring of mothers who had been exposed to the extra vitamin A from fortification during pregnancy had a lower risk of developing T2DM in adult life, compared with offspring of mothers exposed to less vitamin A. Individuals from birth cohorts with the higher prenatal vitamin A exposure (born 1 December 1962-31 March 1964) and those with lower prenatal exposure (born 1 September 1959-31 December 1960) were followed up with regard to development of T2DM before 31 December 2012 in the Danish National Diabetes Registry and National Patient Register. Logistic and Cox regression analyses were performed to determine the risk of T2DM by vitamin A exposure level. A total of 193 803 individuals were followed up until midlife. Our results showed that individuals exposed prenatally to extra vitamin A from fortified margarine had a lower risk of developing T2DM than those exposed to lower levels: OR 0·88; 95 % CI 0·81, 0·95, P=0·001, after adjustment for sex. Fetal exposure to small, extra amounts of vitamin A from food fortification may reduce the risk of T2DM. These results may have public health relevance, as they demonstrate that one of the most costly chronic diseases may be prevented by food fortification - a simple and affordable public health nutrition intervention.

Selective induction of apoptosis by HMG-CoA reductase inhibitors in hepatoma cells and dependence on p53 expression.

HMG-CoA-reductase inhibitors (statins) are widely used drugs to interfere with cholesterol biosynthesis. Besides this usage, evidence is increasing that statins might also be useful in therapy of viral infections or cancer. We investigated the effects of fluva-, simva-, atorva-, rosuva- and lovastatin on the viability of primary mouse and human hepatocytes as well as mouse (Hepa1-6) and human (Huh7, HepG2) hepatoma cell lines. Our results show selective cytotoxic effects of fluva-, simva- and lovastatin on hepatoma cells in comparison to primary hepatocytes. Using human hepatoma cells we found significant reduction of cell viability and induction of apoptosis in HepG2 cells, while statins did not affect Huh7 cells at concentrations not toxic for primary hepatocytes. Stable knockdown of endogenous p53, which is overexpressed in Huh7 cells, was able to restore susceptibility of Huh7 cells towards statin-induced toxicity. The anti-tumor effect of statins did not depend on a lack of cholesterol production, but was restored by supplementation of mevalonate or geranyl-geranyl pyrophosphate, prerequisites for prenylation of small G proteins. In conclusion, statins display a selective apoptotic effect on human hepatoma cells, with fluva-, simva- and lovastatin being both, most selective for tumor cells and most effective in inducing tumor cell apoptosis. Additionally, our results implicate that anti-tumor activity of statins requires cell proliferation and is reduced by p53 overexpression.